JP2008254231A - Multilayered molding and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayered molding using a copolyester for a melt molding, which is obtained only by a melt polycondensation method which provides a molding kept in the transparency of a bottle and enhanced in flavor properties even by long-time continuous operation continuing the molding of a large number of bottles using the same injection mold or a heating stretching mold because the content of a cyclic trimer in the material of the outermost layer or the aldehyde content of acetoaldehyde or the like is reduced by solving the point at issure possessed by a conventional technique, in the outermost layer, and to provide its manufacturing method. <P>SOLUTION: The multilayered molding has a multilayered structure comprising: a layer of a copolyester (A) containing 0.1-10 mol% a copolymer component having a sulfonate base reduced to 30 ppm or below in the content of aldehyde by the degassing treatment of a molten substance after melt polycondensation reaction and set to 7,000 ppm or below in the content of cyclic trimer; and a layer of a thermoplatic polyester (B). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a thermoplastic polyester multilayer molded article used for the production of containers such as bottles and a method for producing the multilayer molded article. More specifically, the present invention relates to a copolymer component having a sulfonate group that has been melt-polycondensed. 0.1% to 10 mol% copolymer polyester layer and thermoplastic polyester layer, low content of cyclic trimers and aldehydes such as acetaldehyde, improved moldability and heat mold contamination, and continuous productivity The present invention relates to a multilayer molded body excellent in the above and a method for producing the same.

Thermoplastic polyesters are excellent in mechanical and chemical properties, and thus have high industrial value, and are widely used as fibers, films, sheets, bottles and the like.
Among these, polyethylene terephthalate (hereinafter sometimes abbreviated as PET) is excellent in mechanical strength, heat resistance, transparency, and gas barrier properties. It is most suitable as a material for molded articles such as beverage filling containers such as beverages.

  Such polyester is supplied to a molding machine such as an injection molding machine to form a preform for a hollow molded body, and the preform is inserted into a mold having a predetermined shape and stretch blow molded to form a hollow for soft drinks. In general, it is formed into a molded container or molded into a heat-resistant or pressure-resistant hollow molded container by heat-treating the preform plug part after heat treatment (crystallization of the plug part) and heat-treating the body part (heat set). Is.

PET contains acetaldehyde (hereinafter sometimes abbreviated as AA) as a by-product during melt polycondensation. In addition, PET produced acetaldehyde by thermal decomposition when thermoforming a molded body such as a hollow molded body, and the acetaldehyde content in the material of the obtained molded body was increased, and the hollow molded body was filled. Affects the flavor and odor of beverages.
For these reasons, various measures have conventionally been taken to reduce the acetaldehyde content in the polyester. As these measures, for example, a method of reducing the AA content by solid-phase polymerization of melt-polycondensed polyester is employed.

  However, in the solid phase polymerization method, the operation of cooling the molten polyester resin to form a chip and performing the solid phase polymerization is necessary, and the operation is complicated, and the preform molding is difficult. Therefore, there is a problem in terms of heat energy, for example, the chip must be remelted.

  On the other hand, a condensation injection molding method has been proposed in which PET obtained by melt polycondensation removes acetaldehyde and simultaneously increases the molecular weight (see, for example, Patent Document 1). However, in such a method, in order to increase the intrinsic viscosity, the residence time in the post-polymerization reactor is as long as 30 to 60 minutes, and there are problems in productivity and coloring, and the cyclic trimer content is reduced. There was also a problem that it was not possible.

  Further, after the melt polycondensation reaction, a molten polyester resin obtained through a vented extruder in a molten state and a method for molding the same (for example, see Patent Documents 2, 3, 4, 5, and 6) are already known. Yes. However, since the cyclic trimer content cannot be reduced even by these techniques, the clogging of the mold of the molding machine and the contamination of the heated stretched mold become severe, and a bottle obtained with a long-time operation is obtained. There is a problem that whiteness is reduced, transparency is lowered, and only bottles having no commercial value can be obtained.

JP-A-8-238643 Japanese Patent No. 3684306 Japanese National Patent Publication No. 11-511187 JP-T-2001-516389 JP 2005-171081 A JP 2005-193379 A

  Therefore, the present invention solves the problems of the above-described conventional technology, and the transparency of the bottle is maintained even during a long continuous operation in which a large number of bottles are formed using the same heated stretch mold, and the flavor property is also improved. It is an object of the present invention to provide a multilayer molded body that gives an improved multilayer stretch molded body and a method for producing the multilayer molded body.

  The inventors of the present invention have arrived at the present invention as a result of intensive studies to achieve the above object. That is, the multilayer molded body of the present invention has a aldehyde content of 30 ppm or less and a cyclic trimer content of 7000 ppm or less, and a copolymer containing 0.1 to 10 mol% of a sulfonate group-containing copolymer component. A multilayer molded article characterized by a multilayer structure comprising a polyester (A) layer and a thermoplastic polyester (B) layer.

In this case, the layer structure may be two or more layers, and the copolymer polyester (A) layer may be the outermost layer and / or the innermost layer.
In this case, the main repeating unit constituting the copolymer polyester (A) and / or the thermoplastic polyester (B) can be ethylene terephthalate.
In this case, the copolymer component having a sulfonate group copolymerized with the copolymer polyester (A) can be a metal salt of 5-sulfoisophthalic acid.
In this case, the haze of the 4 mm-thick molded plate obtained by molding the copolymer polyester (A) at 290 ° C. can be 10% or less.
In this case, the aldehyde content of the thermoplastic polyester (B) layer can be 30 ppm or less.
In this case, the copolyester (A) layer and / or the thermoplastic polyester (B) layer can contain an aldehyde reducing agent.

  In this case, the multilayer molded body according to any one of the above is a hollow molded body preform, a sheet-like preform, or a stretch blow molded body or a stretch formed by stretching these preforms in at least one direction. It can be any of the films.

Moreover, this invention is a manufacturing method of the multilayer molded object characterized by shape | molding the said multilayer molded object from copolymer polyester (A) and thermoplastic polyester (B).
The present invention also relates to a melt of a copolymerized polyester (A) having a cyclic trimer content of 7000 ppm or less, wherein the melt after the melt polycondensation reaction is degassed to reduce the aldehyde content to 30 ppm or less. The melt after the melt polycondensation reaction is degassed and the melt of the thermoplastic polyester (B) whose aldehyde content is reduced to 30 ppm or less is sent to the molding process in the molten state, and the above multilayer molding A method for producing a multilayer molded body, comprising molding a body.

  In the present invention, when the multilayer molded body is a multilayer hollow molded body such as a bottomed multilayer preform, the (most) inner layer is a layer on the inner surface side of the container, and the (most) outer layer is on the outer surface side. Means layer. When the multilayer molded body has three or more layers, the layer sandwiched between the (innermost) inner layer and the (outermost) outer layer is referred to as an intermediate layer. When the multilayer molded body is a multilayer sheet-like product, the (outermost) outer layer and the (outermost) inner layer are both surface layers.

  The present invention relates to a cyclic trimer comprising a copolymer polyester (A) layer and a thermoplastic polyester (B) layer containing 0.1 to 10 mol% of a copolymer component having a sulfonate group that has undergone melt polycondensation. Provided are a multilayer molded article having a low content of aldehydes such as acetaldehyde and excellent in transparency and moldability, a multilayer stretch molded article comprising the same, and a method for producing the same.

Embodiments of the present invention will be specifically described below.
[Copolyester]
The copolymerized polyester (A) according to the present invention is a copolymerized polyester having a repeating unit composed of an aromatic dicarboxylic acid and an aliphatic glycol as a main component, and a copolymer component having a sulfonate group in an amount of 0.1 to 0.1. It is a copolyester containing 10 mol%, preferably 0.5 to 8 mol%, more preferably 1.0 to 5.0 mol%.
Here, content (mol%) of the copolymerization component which has a sulfonate group is a value when the total acid component which comprises copolymerized polyester is 100 mol%.
Moreover, the ratio of aromatic dicarboxylic acid is 70 mol% or more in the total acid component constituting the copolymer polyester, and the ratio of aliphatic glycol in the total glycol component constituting the copolymer polyester is 70 mol% or more. It is preferable that
When the content of the copolymer component having a sulfonate group is less than 0.1 mol%, the cyclic trimer content of the obtained copolymer polyester (A) exceeds 7000 ppm. When continuous stretch blow molding is performed on a multilayer preform with A) as the outermost layer and thermoplastic polyester (B) as the inner layer using a heated mold, mold fouling becomes severe and long-term continuous molding is impossible. This is a problem. On the other hand, if it exceeds 10 mol%, the transparency of the resulting molded article is deteriorated, and the heat resistance of the molded article is lowered because the melting point is lowered, and the color tone is deteriorated due to poor thermal stability. This causes problems and is not preferable.

  As the main dicarboxylic acid component constituting the copolyester (A) according to the present invention, either terephthalic acid or 2,6-naphthalenedicarboxylic acid is most preferable, and is within the range that does not impair the purpose. Acids, diphenyl-4,4′-dicarboxylic acids, aromatic dicarboxylic acids such as diphenoxyethanedicarboxylic acid and functional derivatives thereof, oxyacids such as p-oxybenzoic acid and oxycaproic acid and functional derivatives thereof, adipic acid In addition, aliphatic dicarboxylic acids such as sebacic acid, succinic acid, lactic acid, glycolic acid, and glutaric acid, and functional derivatives thereof can be used.

The main glycol component constituting the copolymer polyester (A) according to the present invention is most preferably ethylene glycol, aliphatic glycols such as 1,3-trimethylene glycol and 1,4-tetramethylene glycol, and cyclohexane diethylene glycol. Alicyclic glycols such as methanol can be used.
In addition, other glycol components, for example, aliphatic glycols such as diethylene glycol, trimethylene glycol, tetramethylene glycol, and neopentyl glycol, alicyclic glycols such as cyclohexanedimethanol, bisphenol A, and bisphenol A are used as long as the purpose is not impaired. Examples include aromatic glycols such as alkylene oxide adducts.

Furthermore, examples of the polyfunctional compound that can be used as a copolymerization component of the copolymer polyester (A) include trimellitic acid and pyromellitic acid as acid components, and glycerin, pentaerythritol, and trimethylol as glycol components. Ethane and trimethylolpropane can be mentioned, and trimellitic acid is particularly preferred. The amount of the copolymer component used should be such that the copolymer polyester (A) is substantially linear.
Monofunctional compounds such as benzoic acid and naphthoic acid may be copolymerized.

  Moreover, as a compound used as the copolymerization component which has a sulfonate group, the dicarboxylic acid or glycol containing a sulfonate group is mentioned, 5-sulfoisophthalic acid, sulfoterephthalic acid, 4-sulfonaphthalene-2,7 Dialkyl esters and / or dihydroxyalkyl esters of metal salt compounds such as dicarboxylic acid and 5- [4-sulfophenoxy] isophthalic acid, or 2-sulfo-1,4-butanediol, 2,5-dimethyl-3 -Metal salt compounds such as sulfo-2,5-hexanediol. As the metal ion, alkali metals such as sodium and potassium lithium, and alkaline earth metals such as magnesium are preferable.

  Examples of the phosphonium salt of a sulfonic acid group-containing aromatic dicarboxylic acid or sulfonic acid group-containing glycol include those represented by the following general formula.

Wherein A is an aromatic group, X1 and X2 are ester-forming functional groups, R1, R2, R3 and R4 are alkyl groups, at least one of which is an alkyl group having 6 to 20 carbon atoms.

  Specifically, sulfo-isophthalic acid tri-n-butyldecylphosphonium salt, sulfoisophthalic acid tri-n-butyloctadecylphosphonium salt, sulfoisophthalic acid tri-n-butylhexadecylphosphonium salt, sulfoisophthalic acid tri-n-butyl Tetradecylphosphonium salt, sulfoisophthalic acid tri-n-butyldodecylphosphonium salt, sulfoterephthalic acid tri-n-butyldecylphosphonium salt, sulfoterephthalic acid tri-n-butyloctadecylphosphonium salt, sulfoterephthalic acid tri-n-butylhexa Decylphosphonium salt, sulfo-terephthalic acid tri-n-butyltetradecylphosphonium salt, sulfoterephthalic acid tri-n-butyldodecylphosphonium salt, 4-sulfonaphthalene-2, 7-dicarboxylic acid tri-n-butyl Rudecylphosphonium salt, 4-sulfonaphthalene-2,7-dicarboxylic acid tri-n-butyloctadecylphosphonium salt, 4-sulfonaphthalene-2,7-dicarboxylic acid tri-n-butylhexadecylphosphonium salt, 4-sulfonaphthalene -2,7-dicarboxylic acid tri-n-butyltetradecylphosphonium salt, 4-sulfonaphthalene-2, 7-dicarboxylic acid tri-n-butyldodecylphosphonium salt, and the like.

  As a compound which becomes a copolymerization component having a sulfonate group, a dicarboxylic acid containing a sulfonate metal base is preferable, and a 5-sulfoisophthalic acid metal salt is particularly preferable.

  The production method of the copolymerized polyester (A) according to the present invention is not particularly limited, and is a direct esterification method with an aromatic dicarboxylic acid, a sulfonate group-containing copolymer component and glycol, or an alkyl ester of an aromatic dicarboxylic acid, An oligomer can be obtained by a transesterification method with a sulfonate group-containing copolymer component and glycol, and then melt polycondensed under normal pressure or reduced pressure to obtain the copolymer polyester (A) according to the present invention. At this time, an esterification catalyst or the polycondensation catalyst may be used as necessary. Subsequently, when the intrinsic viscosity is further increased, or when the aldehyde content or the low cyclic trimer content is set, the melt-polycondensed copolyester thus obtained continues to be subjected to solid phase polymerization. It is preferable to do.

  The melt polycondensation reaction may be performed in a batch reactor or may be performed in a continuous reactor. In any of these methods, the esterification reaction or the transesterification reaction may be performed in one stage, or may be performed in multiple stages. The melt polycondensation reaction may be performed in one stage or may be performed in multiple stages. The melt polycondensation step and the solid phase polymerization step may be operated continuously or may be operated separately.

Below, an example of the preferable manufacturing method by a continuous and a multistage system is demonstrated taking a 5-sodium sulfo isophthalic acid copolymerization polyethylene terephthalate as an example.
First, a slurry containing 1.02 to 2.0 mol, preferably 1.03 to 1.5 mol, of ethylene glycol is prepared for 1 mol of terephthalic acid, and this is continuously added to the esterification reaction step. Supply.
In the esterification reaction, water or alcohol produced by the reaction is removed out of the system by a rectification column under conditions where ethylene glycol is refluxed using a multistage apparatus in which at least two esterification reactors are connected in series. While implementing.
The ethylene glycol solution of 5-sodium sulfoisophthalic acid ethylene glycol ester is preferably added to the esterification reactor in the second and subsequent stages.

  The temperature of the first stage esterification reaction is 240 to 270 ° C, preferably 245 to 265 ° C, and the pressure is 150 to 2000 torr, preferably 300 to 1200 torr. The temperature of the esterification reaction in the final stage is usually 250 to 280 ° C, preferably 255 to 275 ° C, and the pressure is usually 0.1 to 1200 torr, preferably 0.5 to 1000 torr. When carried out in three or more stages, it is preferable to set the reaction conditions for the esterification reaction in the intermediate stage so as to change stepwise from the first stage condition to the final stage condition. It is desirable that the esterification reaction rate in the final stage reaches 90% or more, preferably 93% or more. By these esterification steps, a low-order condensate having a molecular weight of about 500 to 5,000 is obtained.

  In addition, ethylene glycol may dimerize to generate diethylene glycol, which may be copolymerized in the main chain to reduce the strength of the resin. In order to prevent this, tertiary amines such as triethylamine, tri-n-butylamine and benzyldimethylamine, quaternary ammonium hydroxides such as tetraethylammonium hydroxide, tetra-n-butylammonium hydroxide and trimethylbenzylammonium hydroxide are used. It is also preferable to add a small amount of a basic compound such as lithium carbonate, sodium carbonate, potassium carbonate or sodium acetate.

  Subsequently, the obtained low-order condensate is supplied to a multistage liquid phase condensation polymerization process. The polycondensation reaction conditions are as follows: the first stage polycondensation reaction temperature is 250 to 280 ° C., preferably 260 to 280 ° C., and the pressure is 500 to 20 torr, preferably 200 to 30 torr. The temperature is from 255 to 290 ° C, preferably from 260 to 280 ° C, and the pressure is from 10 to 0.1 torr, preferably from 5 to 0.5 torr. When carried out in three or more stages, it is preferable to set the reaction conditions for the esterification reaction in the intermediate stage so as to change stepwise from the first stage condition to the final stage condition. The degree of increase in intrinsic viscosity (IV) achieved in each of these polycondensation reaction steps is preferably distributed smoothly.

The polycondensation reaction is performed using a polycondensation catalyst. As the polycondensation catalyst, it is preferable to use at least one compound selected from Sb, Ge, Ti, or Al compounds. In particular, when the polyester molded body obtained from the copolyester (A) according to the present invention is used for applications in which transparency is an important characteristic, at least one selected from Ge, Ti, or Al compounds. It is preferable to use a compound.
These compounds are added to the reaction system as powders, aqueous solutions, glycol solutions, glycol slurries and the like.

  Examples of the Sb compound include antimony trioxide, antimony acetate, antimony tartrate, antimony potassium tartrate, antimony oxychloride, antimony glycolate, antimony pentoxide, and triphenylantimony. The Sb compound is added so that the amount of Sb remaining in the produced polymer is in the range of 50 to 300 ppm, preferably 50 to 250 ppm, preferably 50 to 200 ppm, and more preferably 50 to 180 ppm. When used in applications where the transparency of the copolyester (A) according to the present invention is a problem, the residual amount of Sb is preferably 200 ppm or less.

  As the Ge compound, amorphous germanium dioxide, crystalline germanium dioxide powder or glycol slurry, a solution obtained by heating and dissolving crystalline germanium dioxide in water, or a solution obtained by adding glycol to this and heat treatment are used. In order to obtain the copolyester (A) used in the invention, it is preferable to use a solution in which germanium dioxide is dissolved by heating in water, or a solution in which glycol is added and heated. In addition, compounds such as germanium tetroxide, germanium hydroxide, germanium oxalate, germanium chloride, germanium tetraethoxide, germanium tetra-n-butoxide, and germanium phosphite can also be used. These polycondensation catalysts can be added during the esterification step. When a Ge compound is used, the amount used is preferably 10 to 150 ppm, more preferably 13 to 100 ppm, further preferably 13 to 50 ppm, and most preferably 15 to 45 ppm as the residual amount of Ge in the copolyester.

  Examples of Ti compounds include tetraethyl titanates, tetraisopropyl titanates, tetra-n-propyl titanates, tetraalkyl titanates such as tetra-n-butyl titanates and partial hydrolysates thereof, titanium acetate, titanyl oxalate, titanyl ammonium oxalate, titanyl oxalate Sodium, titanyl oxalate, titanyl calcium oxalate, titanyl succinate, titanyl succinate, titanium trimellitic acid, titanium sulfate, titanium chloride, titanium halide hydrolyzate, titanium oxalate, titanium fluoride, titanium hexafluoride Titanium with potassium acid, ammonium hexafluorotitanate, cobalt hexafluorotitanate, manganese hexafluorotitanate, titanium acetylacetonate, hydroxy polyvalent carboxylic acid or nitrogen-containing polyvalent carboxylic acid A phosphorus compound is reacted with a complex compound, a composite oxide composed of titanium and silicon or zirconium, a reaction product of titanium alkoxide and a phosphorus compound, or a reaction product of titanium alkoxide and an aromatic polycarboxylic acid or its anhydride. The reaction product obtained by the above. The Ti compound is added so that the amount of Ti remaining in the produced polymer is 0.1 to 50 ppm, preferably 0.5 to 10 ppm.

  Al compounds include aluminum acetate, basic aluminum acetate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride, aluminum carbonate, aluminum phosphate, aluminum phosphonate and other inorganic acid salts, aluminum n-propoxide, aluminum iso-propoxide Aluminum alkoxides such as aluminum n-butoxide and aluminum t-butoxide, aluminum chelate compounds such as aluminum acetylacetonate, aluminum acetylacetate, aluminum ethylacetoacetate, aluminum ethylacetoacetate diiso-propoxide, trimethylaluminum, triethylaluminum, etc. Organic aluminum compounds and partial hydrolysates thereof, aluminum oxide, etc. It is. Of these, aluminum acetate, basic aluminum acetate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride and aluminum acetylacetonate are particularly preferred. The Al compound is added so that the residual amount of Al in the produced polymer is in the range of 5 to 200 ppm, preferably 10 to 50 ppm.

  Moreover, in manufacture of the copolyester (A) based on this invention, you may use together an alkali metal compound or an alkaline-earth metal compound as needed. The alkali metal or alkaline earth metal is preferably at least one selected from Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, and Ba, and the use of an alkali metal or a compound thereof is preferable. More preferred. When using an alkali metal or a compound thereof, use of Li, Na, K is particularly preferable. Examples of the alkali metal and alkaline earth metal compounds include saturated aliphatic carboxylates such as formic acid, acetic acid, propionic acid, butyric acid, and succinic acid, and unsaturated aliphatic carboxylates such as acrylic acid and methacrylic acid. , Aromatic carboxylates such as benzoic acid, halogen-containing carboxylates such as trichloroacetic acid, hydroxycarboxylates such as lactic acid, citric acid and salicylic acid, carbonic acid, sulfuric acid, nitric acid, phosphoric acid, phosphonic acid, hydrogen carbonate, phosphorus Inorganic acid salts such as acid hydrogen, hydrogen sulfide, sulfurous acid, thiosulfuric acid, hydrochloric acid, hydrobromic acid, chloric acid and bromic acid, and organic sulfonates such as 1-propanesulfonic acid, 1-pentanesulfonic acid and naphthalenesulfonic acid , Organic sulfates such as lauryl sulfate, methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, tert-butyl Alkoxides such as alkoxy, chelate compounds and the like acetylacetonate, hydrides, oxides, and hydroxides and the like.

  The alkali metal compound or alkaline earth metal compound is added to the reaction system as a powder, an aqueous solution, a glycol solution, or the like. The alkali metal compound or alkaline earth metal compound is added so that the residual amount of these elements in the produced polymer is in the range of 1 to 50 ppm.

  Furthermore, the copolyester (A) according to the present invention is selected from the group consisting of silicon, manganese, iron, cobalt, zinc, gallium, strontium, zirconium, niobium, molybdenum, indium, tin, hafnium, thallium, tungsten. Further, it may contain a metal compound containing at least one element. These metal compounds include saturated aliphatic carboxylates such as acetates of these elements, unsaturated aliphatic carboxylates such as acrylates, aromatic carboxylates such as benzoic acid, and halogens such as trichloroacetic acid. Hydroxycarboxylates such as carboxylates and lactates, inorganic acid salts such as carbonates, organic sulfonates such as 1-propanesulfonate, organic sulfates such as lauryl sulfate, oxides, hydroxides, chlorides Products, alkoxides, acetylacetonates, and the like, and are added to the reaction system as powders, aqueous solutions, glycol solutions, glycol slurries, and the like. These metal compounds are added so that the residual amount of elements of these metal compounds per ton of the produced polymer is in the range of 0.05 to 3.0 mol. These metal compounds can be added at any stage of the copolyester formation reaction step.

  Further, as stabilizers, phosphoric acid, phosphoric acid esters such as polyphosphoric acid and trimethyl phosphate, phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphonous acid compounds, phosphinic acid compounds, phosphine compounds It is preferable to use at least one phosphorus compound selected from the group consisting of: Specific examples include phosphoric acid, phosphoric acid trimethyl ester, phosphoric acid triethyl ester, phosphoric acid tributyl ester, phosphoric acid triphenyl ester, phosphoric acid monomethyl ester, phosphoric acid dimethyl ester, phosphoric acid monobutyl ester, phosphoric acid dibutyl ester, Phosphoric acid, phosphorous acid trimethyl ester, phosphorous acid triethyl ester, phosphorous acid tributyl ester, methylphosphonic acid, methylphosphonic acid dimethyl ester, ethylphosphonic acid dimethyl ester, phenylphosphonic acid dimethylester, phenylphosphonic acid diethylester, phenylphosphonic acid Diphenyl ester and the like. These stabilizers can be added during the esterification reaction step from a slurry preparation tank of terephthalic acid and ethylene glycol. The P compound is added so that the residual amount of P in the produced polymer is preferably in the range of 5 to 100 ppm.

  When an Al compound is used as the polycondensation catalyst, it is preferably used in combination with a phosphorus compound, and is preferably used as a solution or slurry in which an aluminum compound and a phosphorus compound are previously mixed in a solvent. In the case of an Al compound, a more preferable phosphorus compound is at least one selected from the group consisting of phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphonous acid compounds, phosphinic acid compounds, and phosphine compounds. It is a phosphorus compound. By using these phosphorus compounds, an effect of improving the catalytic activity is seen, and an effect of improving physical properties such as the thermal stability of the copolyester is seen. Among these, use of a phosphonic acid compound is preferable because of its great effect of improving physical properties and improving catalytic activity. Among the above-described phosphorus compounds, the use of a compound having an aromatic ring structure is preferable because the physical property improving effect and the catalytic activity improving effect are great.

  The copolymerized polyester (A) according to the present invention is heated to a predetermined molecular weight in the melt polycondensation reaction apparatus as described above, and then remains in a molten state via a multilayer extruder or an extruder equipped with a deaerator. It is a preferred embodiment that it is sent to a multilayer extruder and molded into a multilayer molded body.

  The intrinsic viscosity of the copolymerized polyester (A) according to the present invention is 0.30 to 0.90 dl / g, preferably 0.40 to 0.85 dl / g, more preferably 0.50 to 0.80 dl / g. is there. If it is less than 0.30 dl / g, the copolymer polyester (A) obtained has a low melt viscosity and insufficient moldability. On the other hand, if it exceeds 0.90 dl / g, since the melt viscosity is high, heat generation becomes severe during molding, the resin temperature rises, thermal decomposition occurs, and the molecular weight is lowered and coloring becomes severe, which becomes a problem.

  Further, the cyclic trimer content of the copolymerized polyester (A) according to the present invention is preferably 6000 ppm or less, and more preferably 5000 ppm or less. If it exceeds 7000 ppm, the mold of the injection molding machine is clogged with a vent, or a multilayer preform with the copolymer polyester (A) as the outermost layer and the thermoplastic polyester (B) as the inner layer is continuously stretched using a heated mold. When blow molding is performed, mold contamination becomes severe, and continuous molding is impossible for a long time, which is a problem. The lower limit of the cyclic trimer is 2500 ppm, and in order to reduce the content to less than this, the content of the sulfonate group-containing component must be 10 mol% or more. Since the melting point of the resulting copolymerized polyester (A) is lowered, problems such as lowering the heat resistance of the molded product and economical problems are undesirable.

  Examples of the method of setting the cyclic trimer content of the copolyester (A) to 7000 ppm or less include a method of setting the content of the sulfonic acid metal base-containing component to 0.1 mol% or more, and a sulfonic acid metal base-containing component. And the like may be added later in the esterification reaction or transesterification reaction. Moreover, the method of combining these methods appropriately can also be implemented.

  In addition, the aldehyde content of the copolymerized polyester (A) according to the present invention may not be a problem depending on the use of the multilayer molded article, but a biaxially stretched multilayer blow filling a beverage or the like in which flavor retention is a problem. When used in the innermost layer of the bottle, it is 30 ppm or less, preferably 20 pm or less. When it exceeds 30 ppm, the flavor retention of the obtained molded article is deteriorated, which is a problem. Further, these lower limits are preferably 0.1 ppb from the viewpoint of production.

  In particular, a copolymerized polyester having ethylene terephthalate as a main repeating unit as the copolymerized polyester (A) according to the present invention is used as a material for the innermost layer of a multilayer container for low flavor beverages such as mineral water. In this case, it is desirable that the acetaldehyde content of the copolyester (A) is 10 ppm or less, preferably 6 ppm or less, more preferably 5 ppm or less, and most preferably 4 ppm or less.

  Here, the aldehydes mean that ethylene glycol is a major component of glycol component, such as polyester whose main constituent unit is ethylene terephthalate and polyester whose main constituent unit is ethylene-2,6-naphthalate. In the case of polyester as a component, it is acetaldehyde or formaldehyde, in the case of polyester having 1,3-propylene terephthalate as a main constituent unit, allyl aldehyde, and in the case of polyester having butylene terephthalate as a main constituent unit. Butanal. However, in the case of a polyester having butylene terephthalate as the main structural unit, the aldehyde is mostly detected as tetrahydrofuran.

As a method of reducing the acetaldehyde content to 30 ppm or less, for example, a method of supplying chips to a multilayer molding machine after being melt-processed by an extruder with a degassing apparatus or a degassing apparatus in a molten state after melt polycondensation Examples include a method of supplying to a multilayer molding machine after the treatment, a method of using an antioxidant such as an aldehyde reducing agent or a hindered phenol in combination with the above methods, and a method of appropriately combining these methods. .
Examples of the degassing apparatus used when aldehydes such as acetaldehyde are reduced by degassing treatment include an extruder with a degassing apparatus and a flash tank.

As the extruder with a deaeration device, either a single screw extruder or a twin screw extruder can be used, but a twin screw extruder is preferable because of the reduction efficiency of aldehydes such as acetaldehyde. Note that the screw of the twin-screw extruder may be any of a meshing type, a non-meshing type, and an incomplete meshing type, or any of the same direction and different direction rotations.
Further, although the flash tank is degassed under reduced pressure conditions, the molten resin flow is sent from the piping to the flash tank via a plurality of dies. The dealdehyde treated melt is sent from the flash tank to, for example, an accumulator, a gear pump or an extruder.

  Although the resin temperature in the degassing apparatus depends on the copolymerization amount of the sulfonate group of the copolyester (A), it is 220 ° C to 300 ° C, preferably 230 ° C to 290 ° C, more preferably 240 ° C to 280 ° C. A range of is desirable. The purpose of the degassing apparatus can be achieved when the degree of pressure reduction is 50 torr or less, preferably 20 torr or less, more preferably 10 torr or less.

  The color b value of the copolyester (A) according to the present invention thus obtained is preferably 6 or less. More preferably, it is 4.0 or less, More preferably, it is 3.0 or less, Especially preferably, it is 2.0 or less, Most preferably, it is 1.5 or less. When the color b value exceeds 6, coloring of the resin obtained with the naked eye is strongly felt, and a preferable molded product cannot be obtained.

  When the dealdehyde treatment is performed from the resin using a degassing apparatus, the resin is considerably colored as compared with the conventional melt polycondensation or solid state polymerization after the melt polycondensation. This is a characteristic phenomenon when dealdehyde is performed from a resin using a degassing apparatus. Causes include shear heat generation between the screw and barrel of the extruder, local deterioration of the resin due to heating of the barrel heater, and slight vacuum leakage between the barrels in the extruder with a deaerator. This is probably because the resin is exposed to oxygen-containing air and the resin is decomposed.

The copolymerized polyester (A) according to the present invention is, for example, (extreme viscosity after an extruder with a degasser)-(limit before an extruder) in order to prevent coloring due to an increase in residence time in the degasser. (Viscosity) is preferably produced in the range of -0.10 to 0.20 dl / g, more preferably in the range of -0.08 to 0.15 dl / g, still more preferably in the range of -0.05 to 0. It can be obtained by producing in the range of .10 dl / g, most preferably in the range of -0.03 to 0.05 dl / g.
(Intrinsic viscosity after extruder with deaerator)-(Intrinsic viscosity before extruder) is lower than -0.10 dl / g, it is not economical, and sometimes the transparency and color tone of the resulting multilayer molded product are Deteriorate. Moreover, if the intrinsic viscosity after the extruder with the deaerator-the intrinsic viscosity before the extruder exceeds 0.20 dl / g, it is necessary to stay in the deaerator-type extruder for a long time, resulting in poor productivity. In addition, adverse effects such as deterioration of the color b value and increase of the AA value occur. The residence time in the reduced pressure region in the extruder with a deaerator is preferably 5 minutes or less. More preferably, it is 4 minutes or less, More preferably, it is 3 minutes or less, Most preferably, it is 2 minutes or less.

  In the present invention, the melt of the copolyester (A) obtained by melt polycondensation is degassed as described above, and then subjected to a multi-layer such as a multi-layer preform molding machine by means of transport such as an extruder or a gear pump. It is transported to the molding machine.

Moreover, the haze of the 4 mm-thick molded plate obtained by molding the copolymerized polyester (A) according to the present invention at 290 ° C. is preferably 10% or less, more preferably 5% or less. When it exceeds 10%, the transparency of the obtained multilayer molded article is poor, resulting in a problem that the commercial value is lost.
Examples of a method of reducing the haze of a 4 mm-thick molded plate molded at 290 ° C. to 10% or less include, for example, a method of setting the copolymerized dialkylene glycol content to 2.0% or more, as a polycondensation catalyst, Ge, Examples thereof include a method using a compound selected from Ti or Al compounds, and a method of appropriately combining these methods can also be carried out.
The content of dialkylene glycol copolymerized in the copolymerized polyester (A) according to the present invention is preferably 1.0 to 5.0 mol of the glycol component constituting the copolymerized polyester (A). %, More preferably, it is 1.5-4.0 mol%, More preferably, it is 2.0-3.0 mol%. When the amount of dialkylene glycol exceeds 5.0 mol%, the thermal stability is deteriorated, the decrease in molecular weight becomes large at the time of molding, and the increase in the content of aldehydes is unfavorable. Further, in order to produce a copolymer polyester (A) having a dialkylene glycol content of less than 1.0 mol%, uneconomic production conditions should be selected as transesterification conditions, esterification conditions or polymerization conditions. Is necessary and the cost is not suitable. Here, the dialkylene glycol copolymerized in the copolymer polyester (A) is, for example, an ethylene glycol which is a glycol in the case of the copolymer polyester (A) whose main structural unit is ethylene terephthalate. Among the diethylene glycols produced as a by-product from the production of diethylene glycol (hereinafter abbreviated as DEG) copolymerized with the copolymer polyester (A), 1,3-propylene terephthalate is In the case of the copolymerized polyester (A) as the main structural unit, di (1,3-propylene glycol) (or bis (3-hydroxypropyl) by-produced from 1,3-propylene glycol, which is a glycol, during production. ) Ether), di (1,3-propylene glycol) copolymerized with the copolymerized polyester (A). Hereinafter referred to as DPG)) is that.

The amount of diethylene glycol copolymerized with the copolymerized polyester (A) according to the present invention, particularly the copolymerized polyester (A) in which the main repeating unit is composed of ethylene terephthalate is the same as that of the copolymerized polyester (A). It is 1.0-5.0 mol% of the glycol component which comprises, Preferably it is 1.3-4.5 mol%, More preferably, it is 1.5-4.0 mol%. When the amount of diethylene glycol exceeds 5.0 mol%, the thermal stability is deteriorated, the decrease in molecular weight becomes large at the time of molding, and the increase in the acetaldehyde content and the formaldehyde content becomes large. On the other hand, when the diethylene glycol content is less than 1.0 mol%, the transparency of the obtained molded article is deteriorated.
The copolymerized polyester (A) according to the present invention includes polyamide, polyesteramide, low molecular weight amino group-containing compound, hydroxyl group-containing compound, hindered phenol compound, hindered amine compound, benzotriazole as an aldehyde reducing agent. Compound, benzophenone compound, polyphenol compound, phosphorus stabilizer, sulfur stabilizer, alkali metal salt can be blended, preferably polyamide, benzophenone compound, polyesteramide, phosphorus stabilizer, low molecular weight An amino group-containing compound, a hydroxyl group-containing compound, a benzophenone compound, a hindered phenyl compound, and a hindered amine compound can be blended. Most preferably, it is a polyamide, a polyesteramide, or a low molecular weight amino group-containing compound, and the haze of the obtained polyester molded article is good.
These polyamide compounds, low molecular weight amino group-containing compounds, hydroxyl group-containing compounds and other aldehyde reducing agents may be used alone or in admixture at an appropriate ratio.

The aldehyde reducing agent is, for example, 0.001 to 5 parts by weight, preferably 0.01 to 3 parts by weight, more preferably 0.1 to 2 parts by weight based on 100 parts by weight of the copolyester (A) according to the present invention. Part by weight can be used.
The aldehyde reducing agent can be blended by adding a predetermined amount of aldehyde reducing agent at any reaction stage from the production of a low-polymerization degree oligomer of polyester to the production of polyester polymer. For example, the aldehyde reducing agent may be added to a reactor such as an esterification reactor or a polycondensation reactor in an appropriate form such as a fine granule, powder, or melt, or from the reactor to a reactor in the next step. The aldehyde reducing agent or a mixture of the polyester and the polyester may be introduced in a molten state into a transport pipe for the polyester reactant.

  The copolymer polyester (A) according to the present invention includes inorganic particles such as calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate, titanium oxide, lithium phosphate, calcium phosphate, and magnesium phosphate, calcium oxalate, High cross-linking of organic salt particles such as terephthalate such as calcium, barium, zinc, manganese and magnesium, and vinyl monomers such as divinylbenzene, styrene, acrylic acid, methacrylic acid, acrylic acid or methacrylic acid. Inactive particles such as molecular particles can also be included.

[Thermoplastic polyester]
The thermoplastic polyester (B) used in the present invention was substantially derived from a carboxylic acid component mainly composed of one or more aromatic dicarboxylic acid components and an alcohol component mainly composed of one or more glycol components. Examples of thermoplastic polyesters include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytrimethylene terephthalate (PTT), and polybutylene terephthalate (PBT). Among them, polyethylene terephthalate is preferable. .

  Further, as the thermoplastic polyester (B), the polyester produced only in the melt polycondensation step described below, and the polyester produced only in the melt polycondensation step were further heat-treated to mainly reduce the cyclic trimer content. Examples thereof include polyesters and polyesters obtained by further solid-phase polymerization of the polyester obtained in the melt polycondensation step to reduce the cyclic trimer content and the aldehyde content.

  In the case of a multilayer molded article having a layer structure of three or more layers and the intermediate layer is a thermoplastic polyester (B), a thermoplastic polyester (B) obtained only by melt polycondensation can be used as the material for the intermediate layer. However, in the case of a multilayer molded body having a two-layer structure and an inner layer of the thermoplastic polyester (B), the melt polycondensation thermoplastic polyester (B) degassed as described later or the heat subjected to solid phase polymerization It is preferable to use the plastic polyester (B) as an inner layer, and it is most preferable to use a solid-phase polymerized product, particularly in the case of use in contact with the contents where flavor retention is a problem.

  The thermoplastic polyester (B) is a linear polyester resin containing 85 mol% or more of a structural unit composed of an aromatic dicarboxylic acid component and a glycol component as main repeating units, and preferably a linear polyester resin containing 95 mol% or more. In the case of polyethylene terephthalate, it is a linear polyester resin containing 85 mol% or more of ethylene terephthalate units as the main repeating unit, and preferably a linear polyester resin containing 95 mol% or more.

  Examples of the dicarboxylic acid component incorporated into the thermoplastic polyester (B) by copolymerization include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4′-dicarboxylic acid, and diphenoxyethanedicarboxylic acid. Aromatic dicarboxylic acid and functional derivatives thereof; p-oxybenzoic acid, oxycaproic acid and other oxyacids and functional derivatives thereof; adipic acid, sebacic acid, succinic acid, glutaric acid and other aliphatic dicarboxylic acids and their functionalities Derivatives, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, and functional derivatives thereof.

  Examples of the glycol component incorporated by copolymerization in the thermoplastic polyester (B) include aliphatic glycols such as ethylene glycol, diethylene glycol, trimethylene glycol, tetramethylene glycol, and neopentyl glycol, and alicyclic glycols such as cyclohexanedimethanol. , Aromatic glycols such as bisphenol A, alkylene oxide adducts of bisphenol A, and the like.

  Furthermore, as other copolymer components composed of a polyfunctional compound that can be incorporated into the thermoplastic polyester (B), examples of the acid component include trimellitic acid, pyromellitic acid, and the like. Examples thereof include glycerin and pentaerythritol. The amount of the copolymer component composed of these polyfunctional compounds must be such that the polyester remains substantially linear.

The thermoplastic polyester used in the present invention is produced by any known polycondensation method in substantially the same manner as the copolymer polyester (A).
Hereinafter, an example of a preferable continuous production method of the thermoplastic polyester (B) according to the present invention will be described using polyethylene terephthalate (PET) as an example, but the present invention is not limited thereto. That is, a direct esterification method in which terephthalic acid is directly reacted with ethylene glycol and, if necessary, other copolymerization components to distill off water and esterify, followed by polycondensation under reduced pressure in the presence of a polycondensation catalyst, or , Produced by a transesterification method in which dimethyl terephthalate, ethylene glycol, and other copolymerization components as required are reacted to distill off methyl alcohol and transesterify, followed by polycondensation under reduced pressure in the presence of a polycondensation catalyst. Is done.

Subsequently, when the intrinsic viscosity is increased or the content of low acetaldehyde or low cyclic trimer is set, the melt polycondensation polymer thus obtained is subsequently subjected to heat treatment or solid phase polymerization.
First, when a low polymer is produced by an esterification reaction, 1.02 to 2.0 mol, preferably 1.03 to 1.4 mol of ethylene glycol is added to 1 mol of terephthalic acid or an ester derivative thereof. The contained slurry is prepared and continuously supplied to the esterification reaction step.
In the esterification reaction, water or alcohol produced by the reaction is removed out of the system by a rectification column under conditions where ethylene glycol is refluxed using a multistage apparatus in which at least two esterification reactors are connected in series. While implementing. The temperature of the first stage esterification reaction is 240 to 270 ° C., preferably 245 to 265 ° C., and the pressure is 0.2 to 3 kg / cm ² G, preferably 0.5 to ² kg / cm ² G. The temperature of the esterification reaction in the final stage is usually 250 to 280 ° C, preferably 255 to 275 ° C, and the pressure is usually 0 to 1.5 kg / cm ² G, preferably 0 to 1.3 kg / cm ² G. . When carried out in three or more stages, the reaction conditions for the esterification reaction in the intermediate stage are conditions between the reaction conditions for the first stage and the reaction conditions for the final stage. The increase in the reaction rate of these esterification reactions is preferably distributed smoothly at each stage. Ultimately, it is desirable that the esterification reaction rate reaches 90% or more, preferably 93% or more. By these esterification reactions, low-order condensates having a molecular weight of about 500 to 5,000 are obtained.

When terephthalic acid is used as a raw material, the esterification reaction can be carried out without a catalyst by the catalytic action of terephthalic acid as an acid, but may be carried out in the presence of a polycondensation catalyst.
Also, tertiary amines such as triethylamine, tri-n-butylamine, benzyldimethylamine, quaternary ammonium hydroxides such as tetraethylammonium hydroxide, tetra-n-butylammonium hydroxide, trimethylbenzylammonium hydroxide, and lithium carbonate When a small amount of a basic compound such as sodium carbonate, potassium carbonate or sodium acetate is added, the proportion of dioxyethylene terephthalate component units in the main chain of polyethylene terephthalate is relatively low (5% relative to all diol components). Mol% or less).

Next, in the case of producing a low polymer by transesterification, 1.1 to 2.0 mol, preferably 1.2 to 1.5 mol of ethylene glycol was contained with respect to 1 mol of dimethyl terephthalate. The solution is prepared and continuously fed to the transesterification step.
The transesterification reaction is carried out while removing methanol generated by the reaction outside the system using a rectification column under the condition that ethylene glycol is distilled back using an apparatus in which 1 to 2 transesterification reactors are connected in series. To do. The temperature of the first stage transesterification is 180 to 250 ° C, preferably 200 to 240 ° C. The temperature of the transesterification reaction in the final stage is usually 230 to 270 ° C., preferably 240 to 265 ° C., and as the transesterification catalyst, fatty acid salts such as Zn, Cd, Mg, Mn, Co, Ca, Ba, carbonates Alternatively, Pb, Zn, Sb, Ge oxide or the like is used. A low-order condensate having a molecular weight of about 200 to 500 is obtained by these transesterification reactions.

  Dimethyl terephthalate, terephthalic acid or ethylene glycol, which is the starting material, includes virgin dimethyl terephthalate derived from para-xylene, ethylene glycol derived from terephthalic acid or ethylene, as well as methanol decomposition from used PET bottles. A recovered raw material such as dimethyl terephthalate, terephthalic acid, bishydroxyethyl terephthalate or ethylene glycol recovered by a chemical recycling method such as decomposition of ethylene glycol or ethylene glycol can also be used as at least part of the starting material. Needless to say, the quality of the recovered raw material must be refined to a purity and quality suitable for the intended use.

  Subsequently, the obtained low-order condensate is supplied to a multistage liquid phase condensation polymerization process. The polycondensation reaction conditions are as follows: the first stage polycondensation reaction temperature is 250 to 290 ° C., preferably 260 to 280 ° C., and the pressure is 500 to 20 torr, preferably 200 to 30 torr. The temperature is 265 to 300 ° C, preferably 275 to 295 ° C, and the pressure is 10 to 0.1 torr, preferably 5 to 0.5 torr. When carried out in three or more stages, the reaction conditions for the intermediate stage polycondensation reaction are conditions between the reaction conditions for the first stage and the reaction conditions for the last stage. The degree of increase in intrinsic viscosity achieved in each of these polycondensation reaction steps is preferably distributed smoothly. A single-stage polycondensation apparatus may be used for the polycondensation reaction.

  As the polycondensation catalyst used in the polycondensation reaction, it is preferable to use at least one compound selected from the same Ge, Ti, Sb or Al compounds as in the case of the copolymer polyester (A).

  The melt polycondensation polyester having a predetermined molecular weight obtained as described above can be obtained by, for example, a method in which the melt polyester is extruded into water after completion of the melt polycondensation and cut in water, or after completion of the melt polycondensation. After being extruded in the form of strands from the pores into the air, the chips are formed into pillars, spheres, squares, plates, etc. by the method of forming chips while cooling with cooling water. Is done.

Moreover, as the cooling water at the time of chip formation of the melt polycondensed polyester, it is preferable to use cooling water satisfying at least one of the following (1) to (4), and more preferably (1) to (4 It is most preferable to use water that satisfies all of the above.
Na ≦ 1.0 (ppm) (1)
Mg ≦ 1.0 (ppm) (2)
Si ≦ 2.0 (ppm) (3)
Ca ≦ 1.0 (ppm) (4)

  The sodium content (Na) in the cooling water is preferably Na ≦ 0.5 ppm, more preferably Na ≦ 0.1 ppm. The magnesium content (Mg) in the cooling water is preferably Mg ≦ 0.5 ppm, more preferably Mg ≦ 0.1 ppm. Further, the content (Si) of silicon in the cooling water is preferably Si ≦ 0.5 ppm, more preferably Si ≦ 0.3 ppm. Furthermore, the calcium content (Ca) in the cooling water is preferably Ca ≦ 0.5 ppm, and more preferably Ca ≦ 0.1 ppm.

  In order to reduce sodium, magnesium, calcium, and silicon in the cooling water, an apparatus for removing sodium, magnesium, calcium, and silicon is installed in at least one place until the industrial water is sent to the chip cooling process. Also, a filter is installed to remove clay minerals such as silicon dioxide and aluminosilicate particles. Examples of the device for removing sodium, magnesium, calcium, and silicon include an ion exchange device, an ultrafiltration device, and a reverse osmosis membrane device.

  When heat-treating the melt polycondensation polymer, for example, according to the method described in JP-B-62-49294, JP-B-62-49295, JP-A-2-298512, or JP-A-8-120062 The thermoplastic polyester (B) in which only the cyclic trimer is reduced without significantly increasing the intrinsic viscosity can be obtained.

In the case of solid-phase polymerization, the melt polycondensed polyester chip is preferably pre-crystallized in a continuous crystallization apparatus having two or more stages in an inert gas atmosphere. For example, in the case of PET, the temperature of 100 to 180 ° C. is 1 minute to 5 hours in the first stage precrystallization, and then the temperature of 160 to 210 ° C. is 1 minute to 3 hours in the second stage precrystallization. In the pre-crystallization of the second and higher stages, it is preferable to perform crystallization step by step at a temperature of 180 to 210 ° C. for 1 minute to 3 hours. The crystallinity of the chip after crystallization is preferably in the range of 30 to 65%, preferably 35 to 63%, and more preferably 40 to 60%. The crystallinity can be obtained from the density of the chip.
Next, solid phase polymerization is performed in an inert gas atmosphere or under reduced pressure at an optimum temperature for the prepolymer so that the increase in intrinsic viscosity due to solid phase polymerization is 0.10 dl / g or more. For example, in the case of PET, the upper limit of the solid phase polymerization temperature is preferably 215 ° C. or lower, more preferably 210 ° C. or lower, particularly 208 ° C. or lower, and the lower limit is 190 ° C. or higher, preferably 195 ° C. or higher. is there.

  In order to prevent the generation of acetaldehyde after completion of the solid phase polymerization, the chip temperature is about 70 ° C. or less, preferably 60 ° C. or less, more preferably 50 ° C. or less within about 30 minutes, preferably within 20 minutes, more preferably within 10 minutes. The following is preferable.

  The intrinsic viscosity of the thermoplastic polyester (B) used in the present invention is 0.45 to 1.20 deciliter / gram, preferably 0.60 to 1.00 deciliter / gram, more preferably 0.70 to 0.90. Desirably, it is in the range of deciliters / gram, most preferably 0.75-0.85 deciliters / gram. When the intrinsic viscosity of the polyester is less than 0.45 deciliter / gram, the mechanical properties of the obtained molded article are poor. If the intrinsic viscosity of the polyester exceeds 1.20 deciliters / gram, the resin temperature becomes high when melted by a molding machine or the like, resulting in severe thermal decomposition and an increase in free low molecular weight compounds that affect the fragrance retention. Or the molded body is colored yellow. In the case of PET, the intrinsic viscosity is preferably in the range of 0.55 to 1.20 deciliter / gram.

  The amount of diethylene glycol copolymerized in the thermoplastic polyester (B) is 1.0 to 5.0 mol%, preferably 1.5 to 4.5 mol%, of the glycol component constituting the polyester. More preferably, it is 1.8-4.0 mol%, More preferably, it is 2.0-3.0 mol%, Most preferably, it is 2.0-2.9 mol%. When the amount of diethylene glycol exceeds 5.0 mol%, the thermal stability is deteriorated, which is not preferable. On the other hand, when the diethylene glycol content is less than 1.0 mol%, the transparency of the obtained multilayer molded article is deteriorated.

When the thermoplastic polyester (B) used in the present invention is a melt polycondensate, the cyclic trimer content is about 10,000 ppm.
Further, the content of the cyclic trimer of the thermoplastic polyester (B) obtained by the heat treatment method or the solid phase polymerization method is desirably 7000 ppm or less, preferably 5000 ppm or less, and more preferably 4000 ppm or less.

  The aldehyde content of the thermoplastic polyester (B) used in the present invention is 30 ppm or less, preferably 20 ppm or less, more preferably 10 ppm or less. When the aldehyde content exceeds 30 ppm, the flavor property of the contents deteriorates, which is a problem.

  Moreover, the haze of the 5 mm-thick molded plate obtained by molding the thermoplastic polyester (B) according to the present invention at 290 ° C. is preferably 20% or less, more preferably 15% or less. When it exceeds 30%, the transparency of the obtained multilayer molded article is poor and the commercial value is lost, resulting in a problem.

As a method for reducing the aldehyde content to 30 ppm or less when a melt polycondensation polyester is used as the thermoplastic polyester (B), the same method as in the case of the copolymer polyester (A) can be carried out.
Among these, the method of using the melt polycondensate in the constituent layer of the multilayer molded body is a preferable method from the viewpoint of economy. The degassing apparatus, the extruder with the degassing apparatus, the flash tank, the accumulator, the gear pump or the extruder used are the same as described above.

  In this invention, although the intrinsic viscosity of the thermoplastic polyester (B) melt supplied to the extruder with a vent which is a deaeration processing apparatus can be made into a desired intrinsic viscosity according to a use, it is 0.55-0. It is desirable that the range be 90 dl / g, preferably 0.60 to 0.85 dl / g, more preferably 0.70 to 0.80 dl / g, and most preferably 0.75 to 0.85 dl / g. When the intrinsic viscosity of the polyester is less than 0.55 dl / g, the mechanical properties of the obtained molded article and the like are poor. In addition, when the intrinsic viscosity of the polyester exceeds 0.90 dl / g, the resin temperature becomes high at the time of melting by a molding machine or the like, the thermal decomposition becomes severe, and free low molecular weight compounds that affect the fragrance retention increase. Or the molded body is colored yellow.

  Further, when the innermost layer of the multilayer molded body of the present invention is made of the thermoplastic polyester (B), the aldehyde content of the thermoplastic polyester (B) melt before the degassing treatment is about 80 ppm or less, preferably 70 ppm or less, More preferably, it is 50 ppm or less. If the aldehyde content of the thermoplastic polyester (B) melt before deaeration treatment exceeds 80 ppm, the aldehyde content of the thermoplastic polyester (B) layer can be reduced to 30 ppm or less even if the deaeration treatment described later is performed. It is a problem with flavor. Of course, when the aldehyde reducing agent described later is used in combination, there is no problem even if the upper limit value of the aldehyde content of the thermoplastic polyester (B) melt before the deaeration treatment is higher.

  The deaeration treatment is performed at a temperature not lower than the melting temperature of the thermoplastic polyester (B) and not higher than 300 ° C., under a reduced pressure of 0.01 to 50 torr, preferably 0.01 to 20 torr, more preferably 0.01 to 10 torr. It is preferable to remove aldehydes such as acetaldehyde in a short time of 0.1 to 10 minutes. The resin temperature during the degassing treatment is preferably in the range of 250 ° C to 290 ° C. The residence time is preferably 10 minutes or less, more preferably 5 minutes or less, still more preferably 4 minutes or less, particularly preferably 3 minutes or less, and most preferably 2 minutes or less.

When the degassing treatment is performed from the resin using an extruder equipped with a degassing device for the same reason as the copolyester, the resin is compared with the case where solid phase polymerization is performed after conventional melt polycondensation or melt polycondensation. The coloring becomes considerably strong.
In order to prevent the thermoplastic polyester (B) melt from coloring due to an increase in the residence time in the extruder with a degassing device, (the intrinsic viscosity after the extruder with the degassing device)-(the intrinsic viscosity before the extruder) is The deaeration treatment is preferably performed in the range of −0.1 to 0.08 dl / g, more preferably in the range of −0.08 to 0.05 dl / g, and still more preferably in the range of −0.05 to 0.02 dl. The deaeration treatment is preferably performed in the range of −0.03 to / g, most preferably in the range of −0.03 to 0 dl / g.

  Similar to the copolyester, it is not economical if (the intrinsic viscosity after the extruder with a deaerator)-(the intrinsic viscosity before the extruder) is lower than -0.10 dl / g, but sometimes obtained is a multilayer molding. The transparency and color tone of the body deteriorates. In addition, if the intrinsic viscosity after the extruder with a deaerator-the intrinsic viscosity before the extruder exceeds 0.08 dl / g, it is necessary to stay in the deaerator-type extruder for a long time, resulting in poor productivity. In addition, adverse effects such as deterioration of the color b value and increase of the AA value occur. The residence time in the reduced pressure region in the extruder with a deaerator is preferably 5 minutes or less. More preferably, it is 4 minutes or less, More preferably, it is 3 minutes or less, Most preferably, it is 2 minutes or less.

  The color b value of the deaerated thermoplastic polyester (B) is 4 or less, more preferably 3.0 or less, still more preferably 2.5 or less, particularly preferably 2.0 or less, and most preferably 1. 5 or less is preferable. If the color b value exceeds 4, the hue of the multilayer molded product is poor, which is a problem.

  In the present invention, the thermoplastic polyester (B) melt obtained by melt polycondensation is degassed as described above, and then multilayer molding such as a multilayer preform molding machine by means of transport such as an extruder or a gear pump. Transported to body molding machine.

The thermoplastic polyester (B) is preferably obtained by deactivating the polycondensation catalyst. Examples of a method for deactivating the polyester polycondensation catalyst include a method in which a polyester chip is contacted with water, water vapor or a water vapor-containing gas after solid phase polymerization.
As another means of deactivating the polycondensation catalyst, a phosphorus compound is blended with the thermoplastic polyester (B) after solid-phase polymerization, and mixed and reacted in the molten state at the time of molding or the like to inactivate the polycondensation catalyst. The method of making it.

Moreover, it is also possible to use together the said aldehyde reducing agent used for copolymerization polyester (A) with thermoplastic polyester (B).
The thermoplastic polyester (B) includes the inorganic particles used in the copolyester (A), organic salt particles such as terephthalate such as calcium, divinylbenzene, styrene, acrylic acid, methacrylic acid, acrylic acid or Inert particles such as crosslinked polymer particles such as a methacrylic acid vinyl monomer alone or a copolymer can also be contained.
Furthermore, the thermoplastic polyester (B) includes a gas barrier resin, an ultraviolet blocking resin, a heat resistant resin, an oxygen scavenger, an oxygen scavenging resin, and an oxygen scavenging resin composition within a range that does not impair the object of the present invention. Can be mixed and used at an appropriate ratio.

[Multilayer molded product]
The layer structure of the multilayer molded article of the present invention is determined according to its use and required characteristics, and two or three layers are generally used, but a molded article having a layer structure larger than that is also possible.
It is necessary to determine characteristics required for the copolymerized polyester (A) and the thermoplastic polyester (B) depending on the layer structure of the multilayer molded body, the thickness of each layer, or the use.

  The shape of the multilayer molded body of the present invention is not particularly limited, and examples thereof include various shapes such as a sheet shape, a film shape, a plate shape, and a hollow molded body having a hollow part. The hollow body includes shapes such as a general beverage bottle shape, a cylindrical shape, a dish shape, and a cup shape as packaging materials. Moreover, a sheet-like, film-like, or plate-like multilayer molded body can be processed by bonding or the like, and used as a bag-like or box-like shape. When the multilayer molded body of the present invention is used as a packaging material such as a container, the surface that comes into contact with the contents, for example, in the case of the hollow molded body, the surface on the hollow portion side is constituted by the thermoplastic polyester layer (B). It is preferable to do this.

The multilayer molded body of the present invention can be molded using a multilayer injection molding machine, a multilayer extrusion molding machine, a multilayer compression molding machine, a multilayer hollow molding machine or the like.
When the multilayer molded body is a multilayer preform for bottles, for example, by a co-injection molding method or a sequential injection molding method as described in JP-A-8-253222, a sandwich molding method of Twin Shot Company, etc. It can be molded.

The multilayer preform of the present invention is, for example, provided between the extruder with a degassing device and the preform injection molding machine after degassing the melt of the thermoplastic polyester (B) from the melt polycondensation reactor. The injection molding apparatus which is stored in the accumulator and then intermittently supplied to the hot runner nozzle for multilayer molded body and the melt-polycondensed copolymer polyester (A) are dried and melted, and then hot runner for multilayer molded body It is possible to perform molding using a co-injection molding machine provided with an injection molding apparatus that intermittently feeds to another flow path of the nozzle.
That is, the thermoplastic polyester (B) melt is provided with a storage tank such as an accumulator between the melt transportation means and the multilayer preform co-injection molding machine, and the continuous resin flow from the extruder is temporarily accumulated. It is possible to form a multilayer molded article by intermittently supplying the stored polyester melt to a hot runner for co-injection molding.

In the case of a heat-resistant bottle or heat-resistant pressure bottle, the mouth portion of the multilayer preform can be thermally crystallized. In general, the thermal crystallization of the mouth is preferably performed before, during, or after preheating the preform prior to stretch blow.
Biaxial stretch blow molding can be performed by a single-stage method or a two-stage method. The preform at the stretching temperature is stretched and stretched in the axial direction in a blow mold at a temperature of 100 to 200 ° C., and gas is blown and stretched in the circumferential direction.

By using a multilayer preform of the present invention as a multilayer molded body, the outermost layer is a layer made of a copolymerized polyester, it is possible to improve the contamination of the blow molding mold, and thus to obtain a heat-resistant stretch bottle with excellent transparency. It is. In addition, since mold contamination is improved, productivity is improved and economical production becomes possible.
The layer structure of the multilayer preform of the present invention is determined according to the use and required characteristics of the multilayer container obtained therefrom. For example, when biaxially stretched into a heat-resistant two-layer stretch container, it is preferable to use a copolymer polyester (A) for the outer layer and a thermoplastic polyester (B) for the inner layer.

  In this case, the cyclic trimer content of the outer layer is 8000 ppm or less, preferably 5000 ppm or less, and more preferably 4000 ppm or less. The aldehyde content in the inner layer is 30 ppm or less, preferably 20 ppm or less, more preferably 15 ppm or less, and most preferably 10 ppm or less.

Moreover, the sheet-like multilayer preform according to the present invention can be obtained, for example, by changing the multilayer injection molding machine in the multilayer preform molding to a multilayer extrusion molding machine.
The obtained sheet-shaped preform can be stretched by a conventionally known stretching method, that is, a uniaxial stretching method, a sequential biaxial stretching method, a simultaneous biaxial stretching method, or the like to obtain a multilayer stretched molded body.
In addition, a sheet-shaped or film-shaped multilayer preform can be formed into a cup shape or a tray shape by a pressure forming method, a vacuum forming method, or the like.

  The copolymerized polyester (A) layer or thermoplastic polyester (B) layer according to the present invention is obtained by forming the polyester into a form such as a molded body or a sheet after being heated and melted by a melt molding machine such as an injection molding machine. It is possible to collect the recovered polyester and the used polyester container, and mix the flake-shaped or chip-shaped polyester that has undergone the steps of foreign matter removal, washing, drying, or re-extrusion. The intrinsic viscosity of these recycled products is preferably about 0.50 to 1.00 dl / g. The blending amount is preferably in the range of 1 to 50% by weight.

The copolymerized polyester (A) and the thermoplastic polyester (B) used in the present invention include a colorant, a pigment, an ultraviolet absorber, a heat stabilizer, an antioxidant, an antistatic agent, other than the above as necessary. A lubricant, a nucleating agent, a release agent, an infrared absorber, and the like can be added within a range that does not impair the object of the present invention.
The multilayer molded body of the present invention is used for containers such as hollow containers, sheet-like objects, tray-like objects, cups, containers for filling beverages and foods, electric wires, coating materials such as metal plates, or fibrous materials. it can.

  The present invention will be further described by the following examples, but the present invention is not limited to these examples. Measurements in the examples were performed as follows.

(1) Intrinsic viscosity (IV)
It calculated | required from the solution viscosity at 30 degreeC in a 1,1,2,2-tetrachloroethane / phenol (2: 3 weight ratio) mixed solvent.

(2) Acetaldehyde content of polyester (hereinafter referred to as “AA”)
Sample / distilled water = 0.2 to 1 g / 2 cc of glass ampoule substituted with nitrogen was sealed and subjected to extraction treatment at 160 ° C for 2 hours. After cooling, acetaldehyde in the extract was subjected to high-sensitivity gas chromatography. Measured graphically and the concentration is expressed in ppm. The said operation is repeated 5 times and let the average value be AA content.
The sample of each layer to be used for measurement is collected by scraping from the molded body, but if isolation is difficult, the resin injected from the molding machine of each layer to the outside of the mold may be used as the sample. (3) The same applies to the subsequent analysis.

(3) Content of polyester cyclic trimer (hereinafter referred to as “CT”)
300 mg of a sample is dissolved in 3 ml of a hexafluoroisopropanol / chloroform mixed solution (volume ratio = 2/3), and further diluted with 30 ml of chloroform. To this is added 15 ml of methanol to precipitate the polymer, followed by filtration. The filtrate was evaporated to dryness, brought to a constant volume with 10 ml of dimethylformamide, and the cyclic trimer was quantified by high performance liquid chromatography. The said operation is repeated 5 times and let the average value be CT content.

(4) Diethylene glycol content of polyester (hereinafter referred to as [DEG content])
Decomposition with methanol, the amount of DEG was quantified by gas chromatography, and expressed as a ratio (mol%) to the total glycol components.

(5) Color b value of polyester and molded article Crystallized polyester and molded article were measured according to Tokyo Denshoku color difference meter TC-1500MC-88 JIS-Z8722 (Hunter color difference). A sample cut into a chip or a chip of about 2 mm square was placed in a glass cell up to the eighth minute. After shaking the cell lightly and packing it closely, resin was added until the lid was made, and the lid was capped. A cell filled with resin was placed on a sample stage and measured. Each time the cell was measured, the cell was rotated about 120 degrees three times, that is, 120 degrees was measured from three directions, and the average was obtained.

(6) Catalyst content of polyester About 1 to 10 g of a sample is put in a platinum crucible and incinerated at about 550 ° C., then dissolved in 6N hydrochloric acid and evaporated to dryness, and the residue is dissolved in 1N hydrochloric acid. This solution was measured with an inductively coupled plasma emission spectrometer manufactured by Shimadzu Corporation.

(7) Haze (Degree%)
A sample was cut out from the molded body (wall thickness 4 mm) of the following (8) and the body (thickness: about 0.45 mm) of the multilayer hollow molded body, and the sample was further cut out with a Nippon Denshoku Co., Ltd. haze meter, model NDH2000. Measurement.

(8) Molding of Stepped Molding Plate A polyester sample is formed with an injection molding machine M-150C-DM type injection molding machine manufactured by Meiki Seisakusho and has a gate part (G) as shown in FIGS. Stepped molding with a thickness of A part thickness = 2 mm, B part thickness = 3 mm, C part thickness = 4 mm, D part thickness = 5 mm, E part thickness = 10 mm, F part thickness = 11 mm. The plate was injection molded. In order to prevent moisture absorption during molding, the inside of the molding material hopper was purged with a dry inert gas (nitrogen gas).
As plasticizing conditions by the M-150C-DM injection molding machine, feed screw rotation speed = 70%, screw rotation speed = 120 rpm, back pressure 0.5 MPa, cylinder temperature is 45 ° C., 250 ° C., and immediately below the hopper, and The cylinder temperature after the nozzle was included (hereinafter referred to as Sx) was set to 290 ° C. The injection conditions are 20% for injection speed and holding pressure, and the injection pressure and holding pressure are adjusted so that the weight of the molded product is 146 ± 0.2g. In this case, the holding pressure is 0.5MPa lower than the injection pressure. It was adjusted.
The upper limit of the injection time and pressure holding time is set to 10 seconds and 7 seconds, respectively, and the cooling time is set to 50 seconds. The total cycle time including the time for taking out the molded product is about 75 seconds.
Although the temperature of the mold is always controlled by introducing cooling water having a water temperature of 10 ° C., the mold surface temperature at the time of stable molding is around 22 ° C.
The test plate for evaluating the characteristics of the molded product was arbitrarily selected from the 11th to 18th shots of the stable molded product after the molding material was introduced and the resin was replaced.

(Copolymerized polyester a)
High purity terephthalic acid and ethyl glycol are continuously supplied to the first esterification reactor containing the reactants in advance, and the average residence time is 3 hours at about 250 ° C. and 0.5 kg / cm ² G with stirring. Reaction was performed. This reaction product was sent to the second esterification reactor, and crystalline germanium dioxide was dissolved in water by heating, ethylene glycol was added thereto, heat-treated catalyst solution and ethylene glycol solution of phosphoric acid, and 5-sodium sulfoisophthalate. A solution of ethylene glycol glycol acid (NSIPAE) in ethylene glycol was continuously added separately to this second esterification reactor so that NSIPAE was 1.0 mol% copolymerized with respect to the total acid components, and stirred. The reaction was carried out at about 260 ° C. and 0.05 kg / cm ² G to a predetermined reactivity. The esterification reaction product is continuously sent to the first polymerization reactor, with stirring at about 265 ° C., 25 torr for 1 hour, then with the second polymerization reactor, with stirring at about 265 ° C., 3 torr for 1 hour, and further Polymerization was conducted at about 275 ° C. and 0.5 to 1 torr with stirring in the third polymerization reactor. Next, the molten resin extracted from the polymerization reactor is degassed through a twin-screw extruder with a degasser at 275 ° C. within a residence time of 10 minutes, and stored in a storage tank. A multilayer preform was molded by a multilayer injection molding machine as described later. The residual amount of Ge was 42 ppm.
Table 1 shows the characteristics of the copolyester a before and after the deaeration treatment with the deaerator.

(Copolymer polyester b)
The reaction was carried out in the same manner as in Example 1 except that the copolymerization amount of NSIPAE was 8.0 mol%, and the resultant was subjected to a multilayer molding machine in the same manner. The results are shown in Table 1. The residual amount of Ge was 45 ppm.

(Copolymer polyester c)
The reaction was carried out in the same manner as in Example 1 except that the copolymerization amount of NSIPAE was 13.0 mol% and antimony trioxide was used as a catalyst, and the resultant was subjected to a multilayer molding machine in the same manner. The results are shown in Table 1. The residual amount of Sb was 400 ppm.

(PET-d)
High purity terephthalic acid and ethyl glycol were continuously supplied to the first esterification reactor containing the reactants in advance, and the reaction was carried out with stirring at about 250 ° C. and 150 kPa for an average residence time of 3 hours. Further, the ethylene glycol solution of germanium dioxide and the ethylene glycol solution of phosphoric acid were continuously fed separately to the first esterification reactor. This reaction product was sent to the second esterification reactor, and the reaction was carried out with stirring at about 260 ° C. and 110 kPa to a predetermined reactivity. The esterification reaction product is continuously sent to the first polycondensation reactor and stirred for about 1 hour at about 265 ° C. and 25 torr, then stirred for about 2 hours at about 265 ° C. and 3 torr for 1 hour. Further, polycondensation was performed at about 275 ° C. and 0.5 to 1 torr with stirring in the third polycondensation reactor. The molten resin extracted from the reactor is degassed via a twin-screw extruder with a degasser at 275 ° C. within a retention time of 10 minutes, and then stored in a storage tank and connected through the multilayer injection molding. A multilayer preform was formed by a machine as described later.
The residual Ge content after the twin-screw extruder with a deaerator was 47 ppm, and the residual P content was 30 ppm.

(PET-e)
In polymerization of PET-d, a melt polycondensation resin having an intrinsic viscosity (IV) of 0.56 dl / g and a DEG content of 2.7 mol% obtained by changing the conditions of the third polycondensation reactor of melt polycondensation As cooling water at the time of chip formation, ion exchange water having a sodium content of 0.2 ppm, a calcium content of about 0.05 ppm, a magnesium content of about 0.06 ppm, and a silicon content of about 0.8 ppm is used. Chip.
After fine removal, this was subsequently crystallized at about 155 ° C. under a nitrogen atmosphere, further preheated to about 200 ° C. under a nitrogen atmosphere, and then sent to a continuous solid-phase polymerization reactor for solid phase polymerization at about 208 ° C. under a nitrogen atmosphere. After the solid-phase polymerization, the fine particles were removed by continuous treatment in the sieving step and the fine removal step.
The obtained PET had an intrinsic viscosity of 0.75 dl / g, an acetaldehyde (AA) content of 3.1 ppm, a cyclic trimer content of 0.31 wt%, and a color b of 0.8. The residual Ge content was 46 ppm and the residual P content was 29 ppm. The results are shown in Table 2.
This is dried in a vacuum dryer and then supplied to the inner and outer layer injection molding machine of the multilayer molding machine.

(PET-f)
Using antimony trioxide as a polycondensation catalyst, an ethylene glycol solution of antimony trioxide and an ethylene glycol solution of phosphoric acid are continuously fed separately to the first esterification reactor, and the temperature of the third polymerization reactor is 280 ° C., A PET homopolymer chip was obtained in the same manner as PET-d except that the temperature from the third polymerization reactor to the pores and the residence time were 300 ° C. and 30 minutes, respectively. However, the extrusion conditions were an extrusion temperature of 300 ° C., a residence time of 10 minutes in the extruder, a deaerator vacuum degree of 3 torr, a sodium content of about 9.5 ppm as a cooling water during chip formation, and a calcium content of Water having about 11.3 ppm, magnesium content of about 6.1 ppm, and silicon content of 15.0 ppm was used. The residual amount of Sb was 420 ppm. The results are shown in Table 2.

Example 1
A multilayer preform having a two-layer structure was molded by a multilayer molding machine that could be molded using a melt of copolyester a degassed as the outer layer resin and a PET-d melt degassed as the inner layer resin. The ratio of the thickness of the outer layer to the inner layer was about 2/8.
The mouth portion of the resulting multilayer preform was crystallized by infrared heating, then biaxially stretched and blown using a LB-01E molding machine manufactured by CORPOPLAST, and then approximately about 150 ° C. in a mold set to about 150 ° C. A heat-resistant bottle was molded by heat setting for 30 seconds. 500 bottles were continuously formed, but there was no problem with the characteristics of the bottles. Table 3 shows the results. The transparency of the bottle was determined with the naked eye.

(Examples 2 and 3)
Bottles were molded in the same manner as in Example 1 using the combinations of resins used listed in Table 3, and evaluated. Table 2 shows the results. The result was no problem.

(Comparative Examples 1 and 2)
Bottles were molded in the same manner as in Example 1 using the combinations of resins used listed in Table 3, and evaluated. Table 3 shows the results. The AA content was high and the transparency of the bottle was poor and problematic.

  The present invention provides a multilayer molded article and a multilayer molded article that can provide a multilayer stretched molded article in which the transparency of the bottle is maintained and the flavor is improved even in continuous operation for a long time in which a large number of bottles are molded using the same heated stretched mold. A method for manufacturing a body is provided.

Plan view of the stepped molded plate used in the examples Side view of the stepped molded plate of FIG.

Explanation of symbols

A Part A part of a stepped molding plate B Part B part of a stepped molding plate C Part C part of a stepped molding plate
D Part D of stepped molded plate
E Part E of stepped molded plate
F Part of stepped molded plate F part G Gate part of stepped molded plate

Claims (10)

A copolymer polyester (A) layer containing 0.1 to 10 mol% of a copolymer component having a sulfonate group, having an aldehyde content of 30 ppm or less and a cyclic trimer content of 7000 ppm or less, and a thermoplastic polyester (B) A multilayer molded article having a multilayer structure comprising layers. The multilayer structure according to claim 1, wherein the layer structure is two or more layers, and the copolymer polyester (A) layer is an outermost layer and / or an innermost layer. The multilayer molded article according to any one of claims 1 and 2, wherein a main repeating unit constituting the copolymer polyester (A) and / or the thermoplastic polyester (B) is ethylene terephthalate. The multilayer molded article according to any one of claims 1 to 3, wherein the copolymer component having a sulfonate group copolymerized with the copolymer polyester (A) is a metal salt of 5-sulfoisophthalic acid. The multilayer molded article according to any one of claims 1 to 4, wherein a haze of a 4 mm-thick molded plate obtained by molding the copolymerized polyester (A) at 290 ° C is 10% or less. The multilayer molded body according to any one of claims 1 to 3, wherein the thermoplastic polyester (B) layer has an aldehyde content of 30 ppm or less. The multilayer molded article according to any one of claims 1 to 6, wherein the copolymerized polyester (A) layer and / or the thermoplastic polyester (B) layer contains an aldehyde reducing agent. The multilayer molded article according to any one of claims 1 to 7, wherein the preform is a hollow molded article, a sheet-like preform, or a stretch blow molded article or a stretch formed by stretching these preforms in at least one direction. A multilayer molded article characterized by being one of films. A method for producing a multilayer molded article, comprising molding the multilayer molded article according to any one of claims 1 to 8 from the copolymerized polyester (A) and the thermoplastic polyester (B). The melt after the melt polycondensation reaction is degassed to reduce the aldehyde content to 30 ppm or less, and the melt of the copolymerized polyester (A) having a cyclic trimer content of 7000 ppm or less, and after the melt polycondensation reaction A melt of the thermoplastic polyester (B) having a aldehyde content reduced to 30 ppm or less by deaeration treatment of the melt is sent to the molding step in a molten state, and the melt is sent to the molding process according to any one of claims 6 to 8. A method for producing a multilayer molded article comprising molding the multilayer molded article.

Images